When your Google password expires, this directly impacts how your accounts syncs on your device. You may be able to log in with an expired password initially (due to the device caching credentials), but you will see an alert populate in the bottom right of your screen (depicted below):
When this occurs, please select the "Sign Out" option, or simply click on the notification. This will redirect you back to the sign in/lock screen page. Please follow the screenshots below:
1. Select "Sign In"
2. Please sign in with your previous credentials. Once signed in, you will be prompted to enter a new password.
3. Once you create a new password, the device will prompt you for your previous password again. ChromeOS encrypts all local data with the password that was previously used, so please ensure that you are aware of this password. Given that the default download path now points to Google Drive, all files should be backed up to Google Drive regardless. We would just like to point this out, as it's been an issue for users in the past.
4. Once the old password is entered/validated, you will receive a prompt stating "Your password has been updated". At this point, the process is done, and you will be redirected to your desktop.
If there are ANY questions or concerns regarding this process, please reach out to the IT helpdesk for further information.